The International Monetary Fund (IMF) said Thursday that the U.S. economy's slow start to 2015 is dragging down the world's growth to the lowest level since the Great Recession. The IMF now forecasts 3.3 percent global growth this year, down from the 3.5 percent it predicted in April, which would be the slowest pace of global growth since the world economy shrank slightly in 2009. The U.S. economy, the world's biggest, shrank at a 0.2 percent annual rate from January to March, hurt by poor winter weather. Last month, the IMF cut the outlook for U.S. growth to 2.5 percent in 2015, from April's 3.1 percent. The American economy grew 2.4 percent in 2014, and the IMF expects the U.S. economy to grow 3 percent in 2016. The IMF expects global growth to improve to 3.8 percent next year. The U.S.'s first-quarter troubles are affecting its neighbors. The IMF cut Mexico's 2015 growth forecast to 2.4 percent from 3 percent and Canada's to 1.5 percent from 2.2 percent. The Fund kept its forecast for Chinese economic growth unchanged at 6.8 percent this year and 6.3 percent in 2016. The IMF predicts that the eurozone will grow 1.5 percent this year, unchanged from April's forecast; Japan will grow 0.8 percent, down from an April forecast of 1 percent; and the Brazilian economy will shrink 1.5 percent, a downgrade from April's forecast for a 1 percent drop.